1. Field of the Invention
The present invention relates to an osteosynthetic implant for the fixation and/or support of flat and tubular bone fragments, particularly in children.
2. Description of the Prior Art
Osteosynthetic implantation is currently practiced primarily in adults. Only in a very limited number of cases, such as, for example, in multiple fractures, is osteosynthetic implantation practiced with children during their growth years. The use of synthetic implants in children may result, it is known, in growth disturbances which require corresponding surgical corrections. Preliminary experiments with osteosynthetic connecting elements were performed, although not specifically with reference to pediatric surgery, using screws made from reabsorbable material. The results of these experiments were not encouraging, particularly as regards implantation of the osteosynthetic connecting elements. The range of application was limited, but the screws generally did not withstand stresses produced during the process of implantation. The screw heads generally broke because the reabsorbable material had insufficient strength. Also, the problem of fixation was not solved for those cases in which the individual bone fragments had to be supported by additional elements such as plates or cerclage units.
Work proceeded from considerations and experiences gained from osteosynthetic implantation in adults. In the use of metal implants, a level of microstability must be attained, that is to say, a level of stability which permits only the smallest movements between the fragments. Microstable connections permit stresses of approximately 60-80 kp over the area of the fracture, without perceptible movements being noted.
The considerable elasticity of bones of children and adolescents in their growth years permits, however, a level of macrostability. Macrostable connections, subjected to a stress of 10-20 kp over the area of the fracture, still permit slight, perceptible movements. The fracture is thereby stable as to support and movement. A microstable osteosynthetic implantation such as is achievable, for example, in adult surgery, is not intended for children and adolescents.
This knowledge is consciously utilized by the inventor to provide a new osteosynthetic implant which is suitable for use in pediatric surgery.